Supported metal catalysts are known and their use in numerous reactions, including the hydrogenation of fatty materials, has been described extensively in the literature. To obtain acceptable catalyst activity for applications involving the hydrogenation of fats, oils and their derivatives, the catalyst should have a high specific metal surface area (metal surface per unit weight of catalyst).
While many methods have been described to effect deposition of metals on support materials, they are not totally satisfactory for the preparation of high surface area supported nickel catalysts. For example, in a common procedure nickel is precipitated on the support in the form of an insoluble oxide, hydroxide, carbonate or the like. It is customary to effect this precipitation at elevated temperatures in the presence of a basic compound, such as alkali hydroxide. As a result of this exposure to the hot alkaline solution significant changes in the surface structure of the support occur. Even when it is possible to effect deposition of nickel oxide or hydroxide on the support without significantly altering the pure structure of the support, subsequent reduction with hydrogen has required temperatures upwards of 400.degree. C. and at these temperatures substantial sintering (coalescing) of the nickel occurs. In either case, the specific surface area of the resulting catalyst is appreciably reduced and the effectiveness of the catalyst for hydrogenation applications is significantly lessened.
It would be highly advantageous if a process were available whereby highly effective supported nickel catalysts useful for the hydrogenation of fatty materials could be prepared. It would be even more desirable and advantageous if conditions employed for the process were such that (a) high specific surface area catalysts could be obtained, (b) the surface and pore structure of the support were not significantly altered during the catalyst preparation, and (c) very fine particles of nickel were uniformly deposited over the entire surface of the support. These and other advantages are realized with the process of the present invention and the improved supported nickel catalysts obtained thereby.